Shown here are the three men responsible for the success of Explorer 1 (America's first Earth satellite), which was launched 31 January 1958. At left is Dr. William H. Pickering, former director of JPL, which built and operated the satellite. Dr. James A. van Allen, center, of the State University of Iowa, designed and built the instrument on Explorer that discovered the radiation belts which circle the Earth. At right is Dr. Wernher von Braun, leader of the Army's Redstone Arsenal team which built the first stage Redstone rocket that launched Explorer 1.

Illustration Showing the Van Allen Belts

This diagram showcases the Van Allen belts, which were first detected by instruments aboard Explorer 1 and Explorer 3. The Van Allen belts were the first major scientific discovery of the space age.

Satellite, Explorer I

Satellite, Explorer I

Satellite, Explorer I

Satellite, Explorer I

Satellite, Explorer I

Satellite, Explorer I

Satellite, Explorer I

Satellite, Explorer I

"Launching the first artificial satellites began the space age and started the Soviet-American space race."

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Collection Item Summary:

This artifact is one of several replicas and flight spare Explorer 1 spacecraft in the collection. It was identified as a fully instrumented flight spare of the Explorer-1 satellite attached to an empty fourth stage Sergeant rocket when it was transferred in 1961 to the collection by the NASA Jet Propulsion Laboratory, the builder of the object. It was initially displayed in the Arts and Industries Building. It was on loan to the Museum of Medical Progress in Madison, WI, (4/70-6/70) and briefly to WETA in Arlington, VA, (6/75-7/75). It was inspected in late 2005 and found to be empty of instrumentation save for the micrometeoroid sensor. But markings in the interior frame indicate it to be "Payload II" which was indeed the flight backup that was sent to James Van Allen's laboratory in Iowa for inspection and testing and then returned to JPL in 1958. That payload was donated to NASM by George Ludwig in 2006 (A20060086). The satellite is displayed in the Milestones of Flight Gallery at NASM.

Explorer-1 was the United States' first successful orbiting satellite. Following the failure of Vanguard in December 1957, the JPL- ABMA group was permitted to adapt the Jupiter-C reentry test vehicle to carry an instrumented satellite into earth orbit. The resulting Explorer-1 satellite was successfully launched and placed into Earth orbit on January 31, 1958. Explorer-1, also known unofficially as Satellite 1958 alpha, transmitted data on micrometeorites and cosmic radiation for 105 days. Data from this and two subsequent Explorer satellites led to the discovery by James Van Allen of a belt of intense radiation surrounding the earth.

Collection Item Long Description:

U.S. Satellite Responses to Sputnik

Launched quickly after Sputnik, the first U.S. test satellite failed when its Vanguard launch rocket exploded. It took almost two months before an Army missile launched Explorer 1 on January 31, 1958. The first successful U.S. satellite contained a cosmic ray detector, a radio transmitter, and temperature and micrometeoroid sensors. Its flight marked America’s entry in the space race, a new Cold War competition.

American Failure

The first U.S. satellite launch effort failed spectacularly when its Vanguard rocket exploded during liftoff on December 6, 1957. The TV-3 satellite payload was recovered after the launch rocket malfunctioned almost immediately after ignition and crashed back onto the launchpad.

The striped front section of Explorer contained the payload; the rear section was a solid-fuel rocket motor. Explorer’s light and dark stripes helped control its temperature. As Explorer spun about its long axis, four flexible antennas extended.

Data Source

National Air and Space Museum

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